Language/Multiple-languages/Culture/Calendars-and-Clocks

This is a list of calendar and timekeeping around the world.

Calendar

name	description
Gregorian calendar	The year one is the year of presumed birth of Jesus of Nazareth. There are 12 months in a year. Days for months are 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31. The start of a day is the midnight at Greenwich added or subtracted by multiples of 1 hour, and in some cases further add or subtract 0.5 or 0.25 of hours. The leap day is placed in the second month. There is 1 leap day every 4 years, except when the year is divisible by 100 and not divisible by 400. (97 leaps in 400 years.)
Chinese calendar	The year one is the year of presumed enthronement of Yellow Thearch. There are 12 or 13 months in a year. The first month is the month with winter solstice. There are 29 or 30 days in a month, determined by the moon phase. The first day of a month is the day with new moon. The start of a day is the midnight. Leap month is the first month without a solar term of an even number. (7 leaps in 19 years.)
Korean calendar	The year one is the year of the foundation of Gojoseon. There are 12 or 13 months in a year. The first month is the month with winter solstice. There are 29 or 30 days in a month, determined by the moon phase. The first day of a month is the day with new moon. The start of a day is the midnight. Leap month is the first month without a solar term of an even number. (7 leaps in 19 years.)
Islamic calendar	The year one is the year of Hijra. There are 12 months in a year. There are 29 or 30 days in a month, determined by the moon phase / There are 30 days in months of an odd number, 29 days in months of an even number. The first day of a month is the day with the first sight of the crescent. The start of a day is at sunset. Month with the leap day is the last month. Year with the leap day is the year when the remainder is over 0.5 days. (11 leaps in 30 years.)

Timekeeping

name	description
European timekeeping	A day is divided by 12 units ‘hour’ (in English) evenly. An hour is divided by 60 units ‘minute’ (in English) evenly. A minute is divided by 60 units ‘second’ (in English) evenly. A leap second is added to the last minute of a day irregularly.
Chinese timekeeping	A day is divided by 12 units ‘時’ evenly. A 時 is divided into 2 parts: ‘初’, ‘正’ evenly. Every 初 and 正 is divided by 4 units ‘刻’ evenly.
Thai timekeeping	A day is divided by 4 periods ‘...โมงเช้า’, ‘บ่าย...โมง’, ‘...ทุ่ม’, ‘ตี...’ evenly. Every such period is divided into 6 parts evenly.